b43: use 8K buffers for 64-bit DMA to workaround hardware bug
Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
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996bc370fa
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14a8083e67
2 changed files with 18 additions and 9 deletions
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@ -419,26 +419,34 @@ static int alloc_ringmemory(struct b43_dmaring *ring)
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gfp_t flags = GFP_KERNEL;
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/* The specs call for 4K buffers for 30- and 32-bit DMA with 4K
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* alignment and 8K buffers for 64-bit DMA with 8K alignment. Testing
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* has shown that 4K is sufficient for the latter as long as the buffer
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* does not cross an 8K boundary.
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*
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* alignment and 8K buffers for 64-bit DMA with 8K alignment.
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* In practice we could use smaller buffers for the latter, but the
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* alignment is really important because of the hardware bug. If bit
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* 0x00001000 is used in DMA address, some hardware (like BCM4331)
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* copies that bit into B43_DMA64_RXSTATUS and we get false values from
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* B43_DMA64_RXSTATDPTR. Let's just use 8K buffers even if we don't use
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* more than 256 slots for ring.
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*/
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u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
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B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
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ring->descbase = dma_alloc_coherent(ring->dev->dev->dma_dev,
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B43_DMA_RINGMEMSIZE,
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&(ring->dmabase), flags);
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ring_mem_size, &(ring->dmabase),
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flags);
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if (!ring->descbase) {
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b43err(ring->dev->wl, "DMA ringmemory allocation failed\n");
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return -ENOMEM;
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}
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memset(ring->descbase, 0, B43_DMA_RINGMEMSIZE);
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memset(ring->descbase, 0, ring_mem_size);
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return 0;
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}
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static void free_ringmemory(struct b43_dmaring *ring)
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{
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dma_free_coherent(ring->dev->dev->dma_dev, B43_DMA_RINGMEMSIZE,
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u16 ring_mem_size = (ring->type == B43_DMA_64BIT) ?
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B43_DMA64_RINGMEMSIZE : B43_DMA32_RINGMEMSIZE;
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dma_free_coherent(ring->dev->dev->dma_dev, ring_mem_size,
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ring->descbase, ring->dmabase);
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}
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@ -161,7 +161,8 @@ struct b43_dmadesc_generic {
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} __packed;
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/* Misc DMA constants */
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#define B43_DMA_RINGMEMSIZE PAGE_SIZE
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#define B43_DMA32_RINGMEMSIZE 4096
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#define B43_DMA64_RINGMEMSIZE 8192
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/* Offset of frame with actual data */
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#define B43_DMA0_RX_FW598_FO 38
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#define B43_DMA0_RX_FW351_FO 30
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